Mineral wool board



June 7, 1966 R. H. ENSLEN ETAL 3,255,073

MINERAL WOOL BOARD Filed Dec. 20, 1961 2 Sheets-Sheet 1 INVENTOR. RICHARD HENSLEN Fnao C. NORGARD xxx ATTORNEY June 7, 1966 R. H. ENSLEN ETAL 3,255,073

MINERAL WOOL BOARD Filed Dec. 20, 1961 2 Sheets-Sheet 2 00 0 000 Q can no 00 oo 00 I I\ aaQ00OOOooooO0O0\0co O o OGOOoOOoOOOOaooOcOooaflaoogo o no oo anon INVENTOR. RICHARD H. ENSLEN FRED C. NoRaARn ATTORNEY United States Patent 3,255,073 MINERAL WOOL BOARD Richard H. Ensien and Fred C. Norgard, Somerville, N.J., assignors to Johns-Manville Corporation, New York, N .Y., a corporation of New York Filed Dec. 20, 1961, Ser. No. 160,881 3 Claims. (Cl. 162209) This invention relates to mineral wool fiberboard; in particular, it relates to a novel method of and apparatus for producing such board.

The fiberboard industry has created an incombustible fiberboard by the substitution of mineral wool fiber for the cellulosic fibers ordinarily utilized. The method of producing such fiberboard, however, presents problems not present in the production of cellulosic fiberboards.

One method of producing fiberboard is by means of a rotating cylinder machine, such as an Oliver machine.

This machine comprises a generally semi-cylindrical vat having a smaller .cylinder mounted for rotation therein such that a substantial portion of the cylinder projects above the vat. A slurry of water, fiber, and binder is introduced into the vat, and is agitated by suitable means as the slurry flows between the vat and the cylinder toward an overflow exit. As a result of such agitation, the fibers are not generally aligned with the flow pattern of the slurry but are arranged in a random and haphazard manner. To cause the solids in the slurry to adhere to the outer surface of the cylinder, a plurality of apertures are provided to connect the outer surface with vacuum compartments within the cylinder. As the cylinder rotates, a particular area thereof passes the agitators in succession so that the solids in the slurry are deposited on the cylinder and are gradually built up in the form of a wet lap. The build-up of the fibers on the cylinder is controlled by the action of the agitators in altering flow characteristics of the slurry passing through the vat and also by the general flow characteristics of the slurry passing circumferentially about the cylinder. The process is continuous, whereby most of the water in a slurry fed into the vat at one side will exit through the perforations in the cylinder, while the solids will adhere to the cylinder in the form of a wet lap. A substantially constant level of slurry is maintained within the vat.

Continued rotation of the cylinder brings the wet lap above the slurry level Where, with the use of a doctor blade, or other such scraping device, the wet lap on the cylinder is removed from the periphery thereof in the form of a wet mat. Uusually, the vacuum control is manipulated in such a manner that there is no vacuum effect on the under side of .the wet lap when it is being removed from the cylinder. Thereafter, the wet mat is processed and dried in a well-known manner to form a finished fiberboard.

The mineral wool fibers utilized with the process of the present invention are of the type manufactured from rock or steel slag, sometimes designated as rock wool. With such mineral wool, 40-50% of the material may be unfiberized and may be in several different particulate forms. Ordinarily, the particles are found in the form of shot, comprising small, hard pellets, but they may also appear in the form of coarse sand.

In slurries containing mineral wool fibers as a major ingredient of the solids, the unfiberized particles tend to settle to the lower portion of the vat and accumulate at the internal wall of the vat between a pair of spaced agitators. As the unfiberized particles accumulate, the agitators become less effective in removing such heavy deposits, and the accumulated unfiberized particles build up to a height of such an extent that eventually they interfere with portions of the wet lap being formed on the outer surface of the cylinder.

The most effective way of avoiding the problems encountered with accumulated shot has heretofore been to clean periodically the bottom of the vat to remove such particles. The accumulation of shot, however, is sufficiently rapid to necessitate cleaning the vat daily, which requires a shutdown of the machine. In addition to the lost time, there is a loss of raw materials, since the unfiberized particles cannot be fed back into the initial operations of the fiberboard machine because this would make the shot content undesirably high.

An object of this invention, therefore, is to provide a process for manufacturing mineral wool fiberboard, which permits substantially full utilization of the raw materials.

Another object of this invention is to provide an improved fiberboard manufacturing machine of the rotating cylinder type with improved means for depositing solids upon the periphery of the rotating cylinder.

A further object of this invention is to provide a novel process and apparatus for manufacturing mineral wool fiberboard which does not require periodic shutdown for cleaning of the apparatus to remove unfiberized particles accumulated therein.

Another object of this invention is to provide a novel process for manufacturing mineral wool fiberboard, which process does not interfere with the solids pickup on a continuously moving foraminous surface.

In brief, this invention provides a plurality of jet sprays interspersed between the agitators of a rotary cylinder fiberboard machine. The jet sprays cause the unfiberized particles which tend to settle to the bottom of the vat to be thrown within the sphere of influence of the agitators. The shot or unfiberized particles are thereby properly intermixed with the fibers in a slurry, and the shot and fibers are continually deposited upon the surface of the rotating cylinder. The continual unfiberized particle pickup is maintained so that there is no shot accumulation, which would tend to interfere with the Wet lap formation on the periphery of the rotating cylinder. The solids content of the slurry is thus utilized fully, downtime of the machine is is eliminated or greatlyreduced, and significant economies of production are realized.

Tim nature of the invention will be more fully understood and other objects may become apparent, when the following detailed description is considered in connection with the accompanying drawing, wherein:

FIG. 1 is a transverse sectional view illustrating a rotating cylinder machine of the Oliver type embodying the spraying means of the present invention; and

FIG. 2 is a cross-sectional view on line 2-2 of FIG. 1.

Referring to FIGS. 1 and 2, a rotating cylinder machine of the Oliver type is indicated at 10 and comprises a generally semicylindrical vat 12 having a hollow cylinder 14 rotatably mounted therein on hearing 16.' One of the bearings 16 is extended for connection to suitable power means, not shown. The cylinder 14 is mounted so that a substantial portion thereof extends above the vat 12, and the distance between the cylinder and one side edge of the vat is greater than the distance between the cylinder and the other side edge of the vat. The larger space constitutes the entrance to the vat while the narrower space is adjacent the overflow of the vat. A plurality of apertures or perforations 18 are provided in the outer surface and through the wall of the hollow cylinder 14 to permit the water in the slurry to be drawn through the cylinder .and out suitable exhaust means by the action of vacuum equipment, which is not shown for the sake of simplicity, but which is well known in the art. A plurality of agitators 20 are spaced between the vat and the cylinder, as is well known in the art. The agitators may take any suitable form but as illustrated here, each agitator comprises a cylinder 21 rotatably mounted in the vat by bearings 22, one of which is extended for connection to suitable power means, not shown. Mounted on the agitator cylinder 21 at spaced points along the length thereof are a plurality of elliptical discs 24 arranged so that they form an angle other than 90 with the axis of the agitator cylinder. I

A plurality of spray pipes 26 are fixedly mounted in the vat adjacent the agitators 20. Each spray pipe 26 is provided with a plurality of openings 28 to provide for the spraying of water jets. One end of each pipe 26 is connected to a common water supply manifold 30 through a connecting pipe 32 and a control valve 34,

of the water emitted through the openings 28. Although the spray pipes may be located adjacent any spot in the vat where unfiberized particles of mineral Wool tend to accumulate, they are illustrated as being arranged between the agitators 20. At any rate, some spray pipes should'be located along the generally horizontal portion of the vat which is more susceptible to the formation of shot deposits than the generally vertical sides thereof. The openings 28 may be arranged in any suitable pattern which will prevent shot accumulation, but are illustrated here as comprising two rows of openings spaced approximately 140 apart and directed toward the internal wall of the vat, which arrangement has been found to prevent the accumulation of unfiberized particles between the agitators 20.

The slurry entering the vat has a higher solids content than slurries generally used with machines of this type. The solids content may range between about 0.75% to about 2% but should preferably be within the range of about 1% to about 1.5%. The reason for this relatively high solids content is to offset the dilution of the slurry caused by introducing water from the spray pipes.

The solids in the slurry comprise a binder, mineral wool particles, both fiberized and unfiberized, and cellulosic fibers. Typical ranges of these ingredients are to 30% binder, 5% to newsprint, and 90% to 60% mineral wool particles. An example of a specific formula is as follows: starch 9%, clay 9%, newsprint 5%, and mineral wool particles 77%.

In the particular embodiment illustrated, the cylinder measured approximately 14 feet in diameter and 13 feet in length. The spray pipes provided had a diameter of 4 inches with A5 inch openings arranged in two parallel rows spaced apart 140. The pressure of the water in the spray pipes ranged between 5-70 pounds per square inch, but a range of 10-15 pounds per square inch was preferred. In this latter pressure range the solids content of the slurry in the vat was maintained at about 1%. As noted above, the solids content of the slurry entering the vat is relatively high and is lowered by the diluting action of the water from the spray pipes. It has been found that the slurry is difiicult to handle when the solids content is about 2% or higher; therefore, the pressure of the water in the spray pipe should be maintained within a range that will maintain the solids content of the slurry at a level which allows the slurry to be easily handled.

' which control valve may be set to control the pressure In operation, as previously mentioned, the direction of flow of theslurry is altered by the agitators20 as it enters the vat. This causes the fibers in the slurry to become interfelted and to adhere to the surface of the rotating cylinder 14 in the form of a wet lap. The unfiberized particles of mineral wool tend to settle to the bottom of the vat in areas of poor circulation, such as between the agitatorsor to one side thereof. Water jets from the spray pipes 26, which are strategically placed in the vat, further churn the slurry, concentrating at the dead spots where the unfiberized particles tend to accumulate. These particles are thus continually mixed with the slurry and deposited with the fibers on the surface of the cylinder 14 so that substantially all of the solids in the slurry are utilized.

While the above described invention has been disclosed in connection with the use of mineral wool fibers, it should be understood that the invention is not limited to their use alone; for example, glass fibers may be used instead of the slag and rock fibers, or glass fibers may be mixed with the slag and rock fibers. It is also contemplated that the invention may be used in connection with organic fibers which present the problem of settling in the vat. In any case, the present invention is particularly well suited for producing fiberboards of a material which tends to settle out of the slurry and form deposits on the vat wall.

It should further be understood that the present invention is not limited to the use of water as the spraying fluid. Other spraying compounds may be used, either alone or in combination with water, so long as the compounds used do not interfere with the formation of the wet lap on the cylinder.

Obviously, many modifications of the present invention are possible in the light of the foregoing disclosure, and such modifications are intended to fall within the spirit and scope of the appended claims.

What we claim is:

, 1. A method of forming a wet mat containing a substantial portion of mineral wool fibers and shot on a rotating cylinder board machine having a vat, rotating cylinder, and a plurality of spaced agitators between the walls of the vat and the cylinder, comprising the steps of introducing into the vat a slurry of solids and water,

said solids containing a substantial portion of mineral wool fibers and mineral wool shot, and introducing a plurality of water jet sprays between certain of the spaced agitators, with the sprays being generally directed at the internal wall of the vat, thereby preventing the mineral shot from settling adjacent the walls, and accumulating a layer of fibers and shot on the cylinder.

2. Apparatus for manufacturing fiberboard on a cylinder machine comprising a rotatable cylinder, a vat extending at least partially around said cylinder for receiving a slurry of solids and water, said slurry comprising a substantial portion of mineral fibers, unfiberized mineral wool particles, and water, a plurality of spaced agitators positioned within the vat to maintain the solids and fibers in agitation, and a plurality of water injectors between the spaced agitators, each water injector being connected to a source of water supply and each injector having a plurality of apertures directed generally toward the internal wall of the vat so that jets of water can be sprayed from the injector toward the vat wall, thereby assisting to keep the mineral shot in continuous circulation.

3. In a board making machine having a vat for receiving a slurry including unfiberized particles, fibers, and water, a rotatable cylinder in said vat for picking up said unfiberized particles and said fibers, and spaced agitators mounted in said vat between the vat wall and the cylinder; the improvement of water injecting means located adjacent at least some of the agitators and the bottom 5 6 0f the vat, the water injecting means being directed at 2,773,764 12/1956 Park 162-145 least partially toward the vat internal wall for circulating 2,852,141 9/ 1958 Landon 210407 the unfiberized particles tending to settle from the slurry. 3,007,841 11/196'1 Bfeiner 162145 3,055,797 9/1962 Bolyard 162--145 References Cited by the Examiner 5 3,065,787 11/ 1962 Rescheneder 162327 UNITED STATES PATENTS FOREIGN PATENTS 9/1934 Powell 162-445 90,763 11/1937 SWC1IL 9/1952 Breyfogle 162-380 1 195 Honenberg 1 2 2 1O DONALL H. SYLVESTER, Primary Exammer. 9 Simps n 16 MORRIS O. WOLK. Examiner. 

1. A METHOD OF FORMING A WET MAT CONTAINING A SUBSTANTIAL PORTION OF MINERAL WOOL FIBERS AND SHOT ON A ROTATING CYLINDER BOARD MACHINE HAVING A VAT, ROTATING CYLINDER, AND A PLURALITY OF SPACED AGITATORS BETWEEN THE WALLS OF THE VAT AND THE CYLINDER, COMPRISING THE STEPS OF INTRODUCING INTO THE VAT A SLURRY OF SOLIDS AND WATER, SAID SOLIDS CONTAINING A SUBSTANTIAL PORTION OF MINERAL WOOL FIBERS AND MINERAL WOOL SHOT, AND INTRODUCING A PLURALITY OF WATER JET SPRAYS BETWEEN CERTAIN OF THE SPACED AGIATORS, WITH THE SPRAYS BEING GENERALLY DIRECTED AT THE INTERNAL WALL OF THE VAT, THEREBY PREVENTING THE MINERAL SHOT FROM SETTING ADJACENT THE WALLS, AND ACCUMULATING A LAYER OF FIBERS AND SHOT ON THE CYLINDER.
 2. APPARATUS FOR MANUFACTUING FIBERBOARD ON A CYLINDER MACHINE COMPRISING A ROTATABLE CYLINDER FOR RECEIVING A SLURRY OF SOLIDS AND WATER, SAID SLURRY COMPRISING A SUBSTANTIAL PORTION OF MINIERAL FIBERS, UNFIBERIZED MINERAL WOOL PARTICLES, AND WATER, A PLURALITY OF SPACED AGITATORS POSITIONED WITHIN THE VAT TO MAINTAIN THE SOLIDS AND FIBERS IN AGITATION, AND A PLURALITY OF WATER INJECTORS BETWEEN THE SPACED AGITATORS, EACH WATER INJECTOR BEING CONNECTED TO A SOURCE OF WATER SUPPLY AND EACH INJECTOR HAVING A PLURALITY OF APERTURES DIRECTED GENERALLY TOWARD THE INTERNAL WALL OF THE VAT SO THAT JETS OF WATER CAN BE SPRAYED FROM THE INJECTOR TOWARDS THE VAT WALL, THEREBY ASSISTING TO KEEP THE MINERAL SHOT IN CONTINUOUS CIRCULATION. 